sort -k2n file | awk '{if ($0!=line) print;line=$0}'


egrep -o '[A-Za-z0-9.]+@[A-Za-z0-9.]+\.[a-zA-Z]{2,4}' m.txt >> m1.txt


sort -k2n m7.1.txt | awk '{if ($0!=line) print;line=$0}'  > m7.2.txt


